package com.bbjob.sec;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

import com.bbjob.entity.JwtUser;
import com.bbjob.sec.util.JwtTokenUtils;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JWTAuthenticationFilter extends UsernamePasswordAuthenticationFilter{
	Logger logger=LoggerFactory.getLogger(getClass());
	private AuthenticationManager authenticationManager;

    public JWTAuthenticationFilter(AuthenticationManager authenticationManager) {
        this.authenticationManager = authenticationManager;
    }

    public Authentication attemptAuthentication(HttpServletRequest request,
                                                HttpServletResponse response) throws AuthenticationException {

        // 从输入流中获取到登录的信息
        try {
            Map<String,String> userMap = new ObjectMapper().readValue(request.getInputStream(), HashMap.class);
            return authenticationManager.authenticate(
                    new CustomUsernamePasswordAuthenticationToken(userMap.get("username"), userMap.get("password"), new ArrayList<>())
            );
        } catch (IOException e) {
            e.printStackTrace();
            throw new BadCredentialsException("错误的登录请求数据。。。");
        }
    }

    // 成功验证后调用的方法
    // 如果验证成功，就生成token并返回

    protected void successfulAuthentication(HttpServletRequest request,
                                            HttpServletResponse response,
                                            FilterChain chain,
                                            Authentication authResult) throws IOException, ServletException {

        // 查看源代码会发现调用getPrincipal()方法会返回一个实现了`UserDetails`接口的对象
        // 所以就是JwtUser啦
        JwtUser jwtUser = (JwtUser) authResult.getPrincipal();
        if(logger.isDebugEnabled()) {
        	logger.debug("jwtUser:" + jwtUser.toString());
        }
        
        String token = JwtTokenUtils.createToken(jwtUser.getUsername(), false);
        // 返回创建成功的token
        // 但是这里创建的token只是单纯的token
        // 按照jwt的规定，最后请求的格式应该是 `Bearer token`
        response.setHeader(JwtTokenUtils.TOKEN_HEADER, JwtTokenUtils.TOKEN_PREFIX + token);
        response.setHeader("Access-Control-Expose-Headers", JwtTokenUtils.TOKEN_HEADER);
    }

    // 这是验证失败时候调用的方法
    
    protected void unsuccessfulAuthentication(HttpServletRequest request, HttpServletResponse response, AuthenticationException failed) throws IOException, ServletException {
    	response.setCharacterEncoding("utf-8");
    	response.getWriter().write("登录失败: " + failed.getMessage());
    }

}
